Radio and intercommunication apparatus and system



O. PLAWCZYK July lo, 1951 RADIO AND INTERCOMMUNICATION APPARATUS AND SYSTEM 4 2 Sheets-Sheet 1 Filed Sept. 2, 1948 Q 25b 24b July 10, 1951 o. PLAWCZYK 2,559,898

RADIO AND INTERCOMMUNICATION APPARATUS AND SYSTEM Filed Sept. 2, 1948 2 Sheets-Sheet 2 Patented July 10, 1951 RADIO AND INTERCOMMUNICATION APPARATUS AND SYSTEM Ow siejPlawczyk, London, England Applicationseptember 2, 1948, Serial N o. "4-7 ,444 *In'Great'Britain September 9, 1947 7 Claims. :1

This invention isconcerned with electric wave intercommunication systems and apparatus and has :for an object the provision of such-systems and apparatus which afiord novel facilities in re- .spect of dual-purpose equipment.

Aparticularobjectof the invention'is the provision of such a novel system and-apparatus :for inter-oflice or other intercommunication service which, forthe purpose of-obtaining amplification of intercommunication signals, is adapted to have ,operatively coupled'thereto a complementary'unit in the form-of an independently usable portable or transportable radioreceiver-amplifier.

According to one feature of the invention an electric wave intercommunication system comprises a main-station unit, which :is operatively associated with .one or more sub-station units .and is arranged and adapted to have coupled electrically thereto a complementary but independently usable radio receiver-amplifier unit, and control means whereby said latter unit, when :so coupled, can beemployed -as an amplifier for .intercommunication signals.

According to another feature of the invention,

such an electric :wave intercommunication systemincludes means whereby asound and-electric wave interconvertingdevice of the radio-receiveramplifier .unit serves as a loudspeaker when the main-station unit is being used for reception and as a microphone device when the main-station unit .is being usedfor transmission. Thus the de- '-.vice,'for example a moving coil transducer, provides service as a loudspeaker for radio reception, when the radio receiver-amplifier is operated independently of the intercommunication system, and also as a 'loudspeakeror:microphone device in respect .of .intercommunication signals.

According'to aiurther featureof the invention an electric wave intercommunication apparatus constituting a main-station .unit adapted for :co- ;operation with .one or more sub-station units, comprises means whereby a complementary ibut independently usable portable .or transportable radio receiver-amplifier unit .canbe .coupledlelecceiving means, whereby the unit can-be detach-.- ably coupled electrically ior use with ;an estate.- s d Part to: "an :intercommunio t on ystem.- The electrical .mtercoupling of the mamstation unit and the radio receiv -amp e 1 and :the -.nature of the control mean oan-be such as to permitzthe latter unit, when so coupled to be e p oyed as an amplifie or interoommun cation signals or as ;a radio receiver alternatiyely. Such an arrangement also p o d oo lit es or aying :the radio-p o ramme i nal ov at least apart ,of the interzfiQmmunication network. Inaddition to the saide eotr 'oel roou li g, the mainvstation unit can be ranged and adapted to provide fonmechanical=connectionbee tween itself and the radio receiyer-amplifier-unit. F r xampl nth m inestat onuh can he orm o provided with one part, of a s stem of in e locking parts, adapted to reoe ve e coperat hs part which isifQlmfid or :proridedh the-oomphmenta y unit. conven entl th main-stat on unit can constitute abase uponwhich :the radio receiver-amplifier n t can-be m u ted ih s ad ily removable manner. i t-some. es leotrioa ,interooup ll and me an ca interloo in of t e two units can be refl ct d y mmo means io example plug and s cket fittin s i 1 fi parts or the respective Other features in the invention will :be mentioned during the cours of the desor ption now :to be g yen with reference to the accom anying dr win s wh ch illustrate, b wa eol e am- .p one emh dimento -t vont on an Wh re- 111! Fi .11 :is a pictorial representa o an'el trio wave intercommnnio ti n system and apparatus accordin to the rinve t oazthis n ement providin int rcomml ioa i h :fa tween a .mainestationaunit nd thr e sub units.

Fi :2 s ws dia ramma i ally he l l il' r ran ement of thewsrstemand apparatusashowndn .3512. 1.

Fi 13 shows dia ramm tic ly th circuit arraneement o an al ernative newe supply for the radio zreceivereamplifier :unit 'shpwn in Figs. :1 and .2, and t Fi 4 shows d ag ammatica l th h ater on it connect on @o the elec onic "r vives in aid radio receiver-amplifier :unit. 7

Ref r n first to Fi a main-station unit is indicated at 25 :and comprises :a teasing, for :example a plastic moulding, which serves ato sac.- pommodate aor zcarryxcertaineelectrical idevides includingfindicatorflamgbs 6,. switcheoperating'press j The audio signal obtained across an anode resistor 3| and is apwhen it is divorced from the intercommunication system and comprises a combined on/off switch and volume control l2, a tuning control [3, a radio or intercom selector l4, a socket 15 for the reception of a co-operating plug [6 (shown disconnected) whereby electrical intercoupling between the units 15 and 9 is obtained,

a socket II for the reception of a co-operating plug on another unit (Fig. 3) and a moving coil loudspeaker arranged behind an opening 18 in the casing. Thereceiver-amplifier is adapted to be energised from A. C. or D. C. electric supply means through a lead [9. Alternatively this unit can be energised from an electric battery in conjunction with a vibratory type high tension supply equipment, as will hereinafter be described,

this facility enabling the unit to be operated in locations where an electric mains supply is not available, for example in a road or other vehicle.

Cables 20a, 29b, 20c serve to interconnect electrically the main-station unit 5 and the sub-station units Zia, 2H), 2 lo. Each of the latter comprises a casing, for example a plastic moulding,

which accommodates a moving coil loudspeaker,

arranged behind an opening 22a, 22b, 22c, and

includes an indicator lamp 23a, 23b, 23c and switch 24a, 24b, 24c. M

The circuit arrangement of the system and apparatus shown in Fig. 1 is indicated diagrammatically in Fig. 2 and that portion pertaining to the radio receiver-amplifier unit will now be described. To simplify the drawings the greater part of the radio frequency section of this receiver-amplifier is not shown in detail, it being deemed sufiicient for the understanding of the invention to indicate that the control grid of an electronic valve VI, receives input signals by way of a change-over switch 25 (operated by selector [4, Fig. 1) from a tuned circuit 26, the latter being coupled, by a coil 2'1, to preceding radio signal stages which are indicated in block form at 28 and receive a radio input from an antenna '29. These radio signal stages can be designated to operate according to a superheterodyne or signal-frequency principle. The valve V1 is adapted to function as a detector in respect of radio signals and, for the alternative position of the switch 25, as an amplifier for audio frequency intercommunication signals which are available across the secondary of a transformer 30.

output of the valve VI is plied, through a capacitor 32, to the control grid of a power valve V2, the anode circuit of which includes the primary of an output transformer 33. Control grid bias for the valves VI and V2 is obtained by means of a cathode resistor 34 shunted by a capacitor 35, in respect of VI and resistors 36' and 31, the latter being shunted by a capacitor 38, in respect of V2. w

' In the case of A. C. mains operation, the H. T.

supply for this receiver-amplifier is obtained by means of a half-wave electronic valve rectifier -39 which is'energised, through voltage dropping :.resistors All audit], by the supplymains'connected across terminal points 42 by means of the cable l9 (Fig. 1). When a D. C. supply mains is employed the rectifier 39 is not called upon to perform its rectifying function. The H. T. supply for V2 is taken direct from the cathode of the rectifier 39 and from across a reservoir capacitor 43 whilst in the case of VI and preceding stages, the H. T. supply is taken by way of a resistor 44 and from across a smoothing capaci-' tor 45. The on/off switch I2 is inserted in the mains supply circuit.

In addition to the provision of the switch 25 and the transformer 30, which are departures from normal radio set design, the arrangements whereby this unit is coupled electrically to the main-station unit are also departures from normal radioset practice. These coupling arrangements comprise the 5-way socket ll, for the re ception of the plug l6, which provides electrical intercoupling in respect of a lead 46 of the mains supply circuit, one end of the coil of a moving coil loudspeaker 41 forming a permanent part of the radio receiver-amplifier unit, one end of the primary of the transformer 30, a lead 48 connected to the earthy chassis of the unit and one end of the secondary winding of the output transformer 33. The socket I! also includes make and break switching contacts 49 which normally are closed and serve to connect. the lead from the loudspeaker 41 to the lead from the secondary winding of the transformer 38 but, upon the insertion of the plug l6, are opened by the plunger 59 of the plug IE to isolate, so far as this coupling is concerned, the said two leads and maintain such isolation until the plug is removed from the socket.

The main-station unit 5 comprises, in addition to the plug l6, a double pole change-over set of contacts 5| and a single pole make and break set of contacts 52. These sets of contacts SI and 52 constitute elements of the lever switch 8 (Fig. 1), the set 5| being actuated when the lever is moved from the central position to the lower position and the set 52 being actuated when the lever is moved from the central to the upper position.

The main-station unit also comprises make and break switches 1a, 1b, 1c and' Inc, which can be actuated, individually, through the intermediary of the push-buttons (Fig.1). Electric indicator lamps 6a, 6b, 6c and 6x are provided and in addition the provision of an audible indication is made available by providing a bell or buzzer 53 which is shunted across the resistor 54, this latter facility being in addition to the buzzer effect obtainable from the use of the loudspeaker 41 of the radio receiver-amplifier unit.

Each of the three sub-station units 2Ia, 21b

and 210 comprises it indicator lamp 23a, 23b and 230, its switch 24a, 24b and 240, and a loudspeaker 55a, 55b and 550 respectively. These three units are connected to the main-station unit 5 by means of the three-line cables 20a, 20b and 200, respectively.

The electrical interconnection of the elements of the units shown in Fig. 2 are such, when the plug l6. and socket l'l are coupled, as to provide the following facilities:

Let it be assumed that the apparatus is being energised from A. C. suppl mains and switch i2 has been closed. For intercom service, selector switch 25 is changed over from the condition shown in Fig. 2 and any one of the sub-stations can be called by operation. of the appropriate For example, 'tocall sub-station Zla. switch 141 is operated, leverswitch 8.1.ism0ved. to

5.. the lower position to change over the contacts and calling switch 1m is operated. These three switching operations have for effect to connect the main supply, by way of lead 46, lamp 623, switch 1x, contacts 5|, to the primary of the transformer 39, so that an alternating wave signal is applied to the grid of valve VI Thus there appears across the secondary of the output transformer 23 a corresponding alternating wave signal. This output signal is applied, by way of switching contacts 52 and switch la, to the loudspeaker 55a of the sub-station unit 2|a, thus producing an audible calling signal in respect of this sub-station. Upon release of the calling switch 1a: the calling signal will terminate. If the main-station operator then desires to listen to the operator at sub-station 2Ia speaking into the loudspeaker unit 55a, he must move the lever switch back to the middle position, for which the switching contacts 5! revert to the condition shown in the drawing. The electric wave signals, created by the loudspeaker 55a functionin as a microphone in respect of the operators voice, are passed by way of switch la and contacts 5| to the primary of the transformer 30, are applied to the grid of valve VI and hence will appear, amplified, across the secondary of the output transformer 33. These output signals are applied, by way of switching contacts 52, to the loudspeaker 41, thus establishing telephonic intercommunication between the operator at the sub-station and the operator of the main-station. When the operator at the main-station desires to speak to the operator at the sub-station, he merely moves the lever switch to the lower position in order to change over the contacts 5|. For this latter circuit condition, electric wave signals, generated by reason of the main-station operator speaking into the loudspeaker 41, are applied by way of switching contacts 5| to the primary of the transformer so and hence, after amplification, from the secondary of the transformer 33 by way of switching contacts 5| and la to the loudspeaker 55a of the sub-station.

If the operator at a sub-station desires to call the operator at the main-station, he has to operate the calling switch on his sub-station unit. Thus, if the operator of sub-station unit 21a desires to call the main-station operator, he must close the calling switch 24a which serves to close the mains-energised circuit comprising the lead 46, resistance 54, buzzer 53, indicator lamp 5a, in-

dicator lamp 23a and loudspeaker 55a. The closing of this circuit and the consequent energisation of indicator lamp 5a and buzzer 53 will give a visual and audible indication to the mainstation operator that sub-station 2| a is calling. The main-station operator should then close the corresponding switch la and, assuming that by this time the operator at the sub-station has released his calling switch, can either listen for speech from the sub-station operator or, after moving the lever switch 8 to the lower position, can speak to the sub-station operator.

In similar mamier the sub-station units- 212) and H0 can be brought into service at will by operation of the appropriate switches and, in view of the foregoing description in respect of sub-station 2| a and the comparative simplicity of the circuit arrangement shown in the drawing, it is deemed unnecessary to describe these circuit connections in detail. a

For radio reception, the selector I4 is operated to bring switch 25 into the condition shown in Fig. 2, for which condition carrier wave sig- 6. nals appearing across the tuned circuit 26 are applied to the control grid VI for detection, the resulting radio programme signals appearing across the secondary of the output transformer 33. When the lever switch 8 is in the central position these radio programme signals are applied to the loudspeaker 41 by way of the switching contacts 5|. If it is desired to relay these radio programme signals to one or more of the sub-stations while also maintaining the signals at the main-station, the lever switch 8 is moved to the upper position which has for effect to close the circuit switching contacts 52. In addition, it is necessary to operate one or other of the switches la, lb or To according to which substation is to be provided with the signals. For example, if it is desired that the sub-station unit 2| 1) shall be so energised, the switch 1b is operated, for which circuit condition the signals appearing across the secondary of the output transformer 33 will, in addition to being applied to the loudspeaker 41 by way of switching contacts 5| to provide a programme at the mainstation, also be applied by way of said contacts 5|, contacts 52 and switch lb to the loudspeaker 55b of the sub-station unit 2ib. If desired all the sub-stations can be supplied with the signals simultaneously. In circumstances where it is desired not to have the radio programme at the main-station, lever switch 8 is moved to the lower position which brings about a changeover of the switching contacts 5! so that the signals appearin across the secondary of the output transformer 33 are now applied by way of the said contacts 5! to the switches la, lb, and To, for distribution to the sub-stations if desired, but not to the loudspeaker 41.

If at any time during the course of relaying radio programme signals, the operator at a substation desires to use the apparatus for intercom service, he can, by operating the calling switch (24a, 2411 or 240), give to the operator at the main-station the audible and visual indications hereinbefore described. It is of course also possible for the operator at the main-station at any time to terminate the radio programme relay and use the apparatus for intercom service.

When the radio receiver-amplifier unit 9 is uncoupled from the main-station unit 5, the disengagement of the plug I6 from the socket ll results in the automatic closing of the switching contacts 49 which serve to connect the speaker 41 across the secondary of the output transformer 33, thus enabling the unit 9 to be operated independently of the intercom system.

As an alternative to energising the apparatus from A. C. supply mains, the circuit arrangements shown in the drawings can also be energised from a D. 0. supply mains, the H. T. supply for the radio receiver-amplifier unit 9 being of the so-called universal type.

Furthermore, the apparatus can be energised from a battery, for example a motor-car battery,v and for this purpose the radio receiveramplifier unit 9 is provided with the socket 15 for the reception of a plug whereby such an alternative power supply unit can be coupled thereto. The electrical interconnections between the eight-way socket I 5 are shown in Fig. 4, from where the interconnections of the heaters of the valve VI and V2, the rectifier 39 and also valve V3 and V4 of the high-frequency stages of the radio receiver circuit, and their association with the terminals 42 of a mains supply circuit will be seen. Fig. 4 also shows the inclusion of an indicator lamp 56 for the radio receiver-amplifier unit.

The alternative power supply unit is shown in Fig. 3 and includes an eight-Way plug 51 for use with the socket l5. This supply unit also incorporates an H. T. converter 58 of the vibratory type which is adapted to be energised by a suitable battery which can be connected across terminals 59. The electrical interconnections of this unit are clearly shown in the drawing.

. What I claim and desire to secure by Letters Patent 01 the United States of America is:

1. An electric wave intercommunication system comprising a main station unit, a plurality of sub-station units, means electrically connecting said sub-station units to said main station unit, a separate radio receiver-amplifier unit capable of use independently of said station units, means mechanically coupling said radio receiver-amplifier unit and said main station unit, means electrically coupling said radio receiver-amplifier unit and said main station unit, and control means for selectively effecting operation of said radio receiver-amplifier unit as a radio receiver or as an amplifier for said main station unit and said sub-station units.

2. An electric wave intercommunication system comprising a main station unit, a plurality of sub-station units, means electrically connecting said sub-station units to said main station unit, a separate radio receiver-amplifier unit capable of use independently of said station units, means mechanically coupling said radio receiver-amplifier unit and said main station unit, means electrically coupling said radio receiver-amplifier unit and said main station unit, first control means for selectively effecting operation of said radio receiver-amplifier unit as a radio receiver or as amplifier for said main station unit and said sub-station units, and second control means for selectively controlling the electrical connection between each of said substations and said main station.

3. An electric wave intercommunication system comprising a main station unit, a plurality of sub-station units, means electrically connecting said sub-station units to said main station unit, a radio receiver-amplifier unit adapted to be detachably connected mechanically to said main station unit, whereby said radio receiver'- ainplifier unit is independently usable as a radio receiver, and means electrically coupling said radio receiver-amplifier unit to said main station unit, whereby said radio receiver-amplifier unit is usable as a radio receiver or as an amplifier for said main station unit and said substation units.

4. An electric wave intercommunication system comprisin a main station unit, a plurality of sub-station units, means electrically connecting said sub-station units to said main station unit, a radio receiver-amplifier unit detachably connected mechanically to said main station unit and including a radio receiver and an amplifier, means electrically coupling said radio receiver andsaid amplifier, other means electrically coupling said main station unit and said amplifier, and control means for selectively controlling the electrical connections between said radio receiver and said amplifier, between said main station unit and said amplifier and between said main station unit and said sub-station units.

5. An electric wave intercommunication sys-v tem comprising a main station unit, a plurality of sub-station units, means electrically connecing said sub-station units to said main station unit, a radio receiver-amplifier unit detachably connected mechanically to said main station unit whereby said radio receiver-amplifier unit is usable independently of said station units, and means electrically coupling said radio receiveramplifier unit and said main station unit, said radio receiver-amplifier unit includin an electric wave interconnecting device usable as a loud-.- speaker when said main-station unit is being used for reception and as a microphone when said main-station unit is being used for transmission.

6. An electric wave intercommunication system comprising a main station unit, a plurality of sub-station units, means electrically connecting said sub-station units to said main station unit, a radio receiver-amplifier unit detachably connected mechanically to said main station unit whereby said radio receiver-amplifier unit is usable independently of said station units, means electrically coupling said radio receiver-amplifier unit and said main station unit, and control means for selectively effecting operation of said radio receiver-amplifier unit as a radio receiver or as an amplifier for said main station unit and said sub-station units, said radio receiver-amplifier unit including a moving coil transducer usable as a loudspeaker for radio reception when said radio receiver-amplifier unit is operated as a radio receiver, as a loudspeaker when said main station unit is being used for reception from said sub-station units, and as a microphone when said main station unit is being used for transmission to said sub -station units.

7. An electric wave intercommunication system according to claim 1, wherein said electrical coupling means and said control means are arranged to provide facilities for relaying radio program signals received by said radio receiveramplifier unit when used as a radio receiver to said sub -station units.

OWSIEJ PLAWCZYK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,922,415 Bank Aug. 15, 1933 2,087,027 Glaser July 13, 1937 2,157,140 Molin May 9, 1939 2,159,632 Morey May 23, 1939 2,186,500 Schnell Jan. 9, 1940 2,409,481 Fordham Oct. 15, 1946 

